Inkjet print head

Abstract

An inkjet print head includes a piezoelectric actuator plate and first through third ink channel plates, which are stacked and bonded together by a thermo-setting adhesive. The piezoelectric actuator plate is made of a material (such as lead zirconate titanate) that has a linear expansion coefficient smaller than those of the first through third ink channel plates. The piezoelectric actuator plate is bonded to the first ink channel plate, which is formed of a material (aluminum alloy, for example) having the linear expansion coefficient larger than those of the second and third ink channel plates. The second and third ink channel plates are formed of ferritic stainless steel or the like, and are stacked on the bottom of the first ink channel plate. No warping or deformation occurs in the overall inkjet print head when the print head is returned to room temperature after the adhesive bonding process. The plates in the inkjet print head are formed of materials that have good resistance to the corrosion of ink, thereby increasing the life of the inkjet print head.

What is claimed is:  
     
       1. An inkjet print head, comprising: 
       a piezoelectric actuator plate for being driven by a drive voltage;  
       first and second ink channel plates, each being formed with a plurality of ink channels for guiding ink, the first and second ink channel plates being stacked one on the other, the first ink channel plate being located between the piezoelectric actuator plate and the second ink channel plate and the first ink channel plate having a linear expansion coefficient greater than linear expansion coefficients of the second ink channel plate and the piezoelectric actuator plate; and  
       a thermo-setting adhesive layer provided, between the piezoelectric actuator and the first ink channel plate, for bonding the piezoelectric actuator plate to the first ink channel plate.  
     
     
       2. An inkiet print head as recited in  claim 1 , wherein the linear expansion coefficient of the first ink channel plate is substantially greater than or equal to a product of the linear expansion coefficient of the second ink channel plate and the value of 1.3. 
     
     
       3. An inkjet print head as recited in  claim 2 , wherein the linear expansion coefficient of the first ink channel plate is substantially greater than or equal to a product of the linear expansion coefficient of the second ink channel plate and the value of 1.7. 
     
     
       4. An inkjet print head as recited in  claim 1 , wherein the linear expansion coefficient of the piezoelectric actuator plate is smaller than the linear expansion coefficients of the first and second ink channel plates. 
     
     
       5. An inkjet print head as recited in  claim 1 , 
       wherein the first ink channel plate is formed with a plurality of pressure chambers, which are arranged along a single plane to accommodate ink therein and which are used for selective ejection, and  
       wherein the piezoelectric actuator plate spans across the plurality of pressure chambers and has a plurality of activation portions for being selectively driven to apply pressure to the respective pressure chambers, thereby causing eject ink to be ejected from the pressure chambers.  
     
     
       6. An inkjet print head as recited in  claim 5 , 
       wherein the second ink channel plate has a pair of opposite sides, the first ink channel plate being provided on one side of the second ink channel plate,  
       further comprising a third ink channel plate provided on the other side of the second ink channel plate, and  
       wherein the third ink channel plate being formed with a manifold for supplying ink to the plurality of pressure chambers, the second ink channel plate being formed with a plurality of through-holes for communicating the manifold to the plurality of pressure chambers, the linear expansion coefficient of the third ink channel plate being smaller than the linear expansion coefficient of the first ink channel plate.  
     
     
       7. An inkjet print head as recited in  claim 6 , wherein the first through third ink channel plates are formed of a material that is resistant to ink corrosion. 
     
     
       8. An inkjet print head as recited in  claim 6 , wherein the first ink channel plate is formed of a metal material, and each of the second and third ink channel plates is formed of either one of a metal material and a ceramic material. 
     
     
       9. An inkjet print head as recited in  claim 8 , wherein the first ink channel plate is formed of a metal material, the second ink channel plate is formed of a metal material, and the third ink channel plate is formed of a ceramic material. 
     
     
       10. An inkiet print head as recited in  claim 8 , wherein the first ink channel plate is formed of a metal material, the second ink channel plate is formed of a ceramic material, and the third ink channel plate is formed of a metal material. 
     
     
       11. An inkjet print head as recited in  claim 8 , wherein the first ink channel plate is formed of a metal material, both of the second and third ink channel plates are formed of a metal material. 
     
     
       12. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an aluminum alloy, the second ink channel plate is made of austenitic stainless steel, and the third ink channel plate is made of an austenitic stainless steel. 
     
     
       13. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an aluminum alloy, the second ink channel plate is made of ferritic stainless steel, and the third ink channel plate is made of ferritic stainless steel. 
     
     
       14. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an austenitic stainless steel, the second ink channel plate is made of ferritic stainless steel, and the third ink channel plate is made of ferritic stainless steel. 
     
     
       15. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an austenitic stainless steel, the second ink channel plate is made of titanium alloy, and the third ink channel plate is made of titanium alloy. 
     
     
       16. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an austenitic stainless steel, the second ink channel plate is made of ferritic stainless steel, and the third ink channel plate is made of titanium alloy. 
     
     
       17. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an austenitic stainless steel, the second ink channel plate is made of titanium alloy, and the third ink channel plate is made of ferritic stainless steel. 
     
     
       18. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an austenitic stainless steel, the second ink channel plate is made of titanium alloy, and the third ink channel plate is made of glass. 
     
     
       19. An inkjet print head as recited in  claim 6 , wherein the piezoelectric actuator plate is made of lead zirconate titanate, the first ink channel plate is formed of an austenitic stainless steel, the second ink channel plate is made of glass, and the third ink channel plate is made of titanium alloy.